DEV Community: Simanta Das

What Sololearn Got Right (And What I'm Trying to Fix)

Simanta Das — Tue, 16 Jun 2026 09:37:56 +0000

I'm not here to trash Sololearn.

Sololearn taught millions of people how to code. It was one of the first apps to make programming education feel mobile-native. That's a real achievement. I respect it.

But I'm building Codino — a Python learning app — and I'd be lying if I said I didn't study Sololearn carefully before writing a single line of code. I looked at what they got right. I looked at where users complained. And I made decisions based on both.

This is that honest breakdown.

What Sololearn Got Right

1. The Community Feel

Sololearn built a genuine community. The code playground where users share their projects, comment on each other's code, and get likes — that was smart. Learning feels less lonely when other people are doing it alongside you.

It created a social loop that kept people coming back even when they weren't actively doing lessons.

I haven't built this yet in Codino. The leaderboard is a start, but a full community layer is something I'm thinking about for a future update.

2. Multi-Language Support

Sololearn didn't bet on just one language. Python, JavaScript, C++, SQL, HTML — they covered everything. That gave them a massive addressable audience.

Codino is Python-only right now. That's intentional — going deep on one language is better than going shallow on ten. But I understand why multi-language eventually matters for scale.

3. The Code Playground

The ability to write and run real code inside the app — without going to a browser — was ahead of its time when Sololearn launched it. That feature alone brought back users who had finished all the lessons.

Codino has a full offline IDE powered by Sora Editor. I'd argue ours is actually more capable — real syntax highlighting, autocompletion, offline Python execution — but Sololearn deserves credit for proving this feature matters.

4. Bite-Sized Lessons That Actually Work

Sololearn understood that people learn on the bus, in bed, waiting in line. Their lessons are short, digestible, and don't demand 45 minutes of focus. That format works.

Codino follows the same philosophy. Short lessons, horizontal scrolling, one concept at a time. I didn't copy Sololearn — I copied the truth that they happened to figure out first.

Where Sololearn Left Users Behind

1. The Ads Are Brutal

Sololearn's free tier is heavily monetized with ads. Video ads between lessons. Banner ads. The learning flow gets interrupted constantly.

When you're trying to focus on a new concept, an ad breaks your concentration. That's not a small thing. That's the core product experience being damaged for revenue.

Codino has zero ads. Not "fewer ads." Zero. I believe if you interrupt someone's learning moment for revenue, you've chosen money over the user. I'm not doing that.

2. No Real AI Tutor (Free)

Sololearn added an AI feature called "Sololearn AI." It's paywalled. If you want AI to explain a concept or help debug your code, you pay.

The students who need the most help are usually the ones with the least money.

Codino gives every user free daily AI credits powered by Gemini and Groq as fallback. You get real AI explanations, code debugging help, and lesson hints — for free, every day.

3. The Certificate Costs Money

After finishing a Sololearn course, you can earn a certificate. But downloading and sharing a verified certificate requires a paid subscription.

You did the work. You finished the course. But the proof of it is locked behind a paywall.

Codino gives certificates for free. You finish the Python course, you get the certificate. No payment required. That's just fair.

4. No Data Science Library Support

Sololearn lets you run Python code. But try importing NumPy or Pandas — it won't work. Their code runner doesn't support real scientific libraries.

For anyone learning Python for data science or machine learning, this is a dead end.

Codino supports 20+ real libraries — NumPy, Pandas, Matplotlib, Scikit-Learn — through Pyodide running inside a Jupyter-style notebook. You can do real data science on your phone, offline.

5. The IDE Feels Like a Toy

Sololearn's code editor is functional but minimal. No real autocompletion. No advanced syntax highlighting. It feels like a demo, not a real development environment.

Codino uses Sora Editor — a full-featured, open-source Android code editor. It feels like a real IDE because it is one.

The Honest Summary

Feature	Sololearn	Codino
Ads	Yes, heavy	Zero
AI Tutor	Paid only	Free daily credits
Certificate	Paid only	Free
Offline IDE	Basic	Full (Sora Editor)
Data Science Libraries	Not supported	20+ via Pyodide
Community	Large, active	Early stage
Languages	Many	Python only (for now)

What I'm Still Working On

Sololearn has years and millions of users on me. There are things they've figured out that I'm still learning:

Community building — People coming back to share and connect, not just learn
Breadth — More languages eventually
Scale — Making everything work smoothly for thousands of users, not just hundreds

I'm one developer. Codino is a few months old. But the foundation is honest, the tools are free, and the user never pays for the things that should be free.

That's what I'm building toward.

Codino is available on the Google Play Store. Search "Codino Learn Python."

If you've used Sololearn and want to share your experience — comment below. I genuinely read everything.

I Shipped a Python Learning App with Zero Money — Here's Every Free Tool I Used

Simanta Das — Tue, 16 Jun 2026 08:08:54 +0000

*A 19-year-old developer from Bangladesh. No funding. No team. Just free tools, free APIs, and stubbornness. *

I'm Simanta. I built Codino — a Python learning app with an offline IDE, AI tutor, Jupyter-style notebook, gamification, and data science library support — and published it on the Google Play Store.

My total budget: $0.

This is the complete breakdown of every single tool I used, why I chose it, and exactly how it fits into the app. No fluff.

The Stack at a Glance

What I needed	Free tool I used
Code editor with syntax highlight	Sora Editor
Python in the browser/notebook	Pyodide + Skulpt
AI tutor with generous free tier	Google Gemini API
Extra AI fallback providers	Groq, OpenRouter
Backend (no-cost)	Supabase free tier
UI framework	Jetpack Compose
App distribution	Google Play Store

1. Sora Editor — The Code Editor That Saved Me Months

Building a code editor from scratch for Android is a nightmare. Syntax highlighting, auto-indentation, bracket matching, line numbers — all of that is extremely hard to implement yourself.

Sora Editor is a free, open-source rich-code-editor library for Android. I plugged it directly into Jetpack Compose and got a fully working IDE in hours instead of months.

What it gave me for free:

Syntax highlighting for Python (and other languages)
Autocompletion support
Smooth scrolling even on low-end Android devices
A clean, dark-theme-friendly design

If you're building any kind of coding or text-heavy Android app, use Sora Editor. There is no reason to reinvent it.

GitHub: github.com/Rosemoe/sora-editor

2. Skulpt — Running Python Instantly in Lessons

For the lesson-based IDE (the basic code runner students use during lessons), I used Skulpt.

Skulpt is a JavaScript implementation of Python. It runs Python code entirely in the browser/WebView — no server, no internet, no waiting.

Why Skulpt over something heavier:

Extremely lightweight
Loads instantly inside a WebView
Perfect for beginner-level Python (variables, loops, functions, conditionals)
Zero cost, zero server calls

The limitation: it doesn't support advanced libraries like NumPy. But for the lesson environment, it's perfect.

3. Pyodide — Real Python for the Jupyter-Style Notebook

For Codino's notebook feature (the JupyterLab-style cell interface), I needed something more powerful — something that could actually run NumPy, Pandas, and Matplotlib.

That's where Pyodide comes in.

Pyodide is CPython compiled to WebAssembly. It runs real Python inside a browser. It supports 20+ scientific libraries including:

numpy
pandas
matplotlib
scikit-learn

I embedded Pyodide inside an Android WebView and built the cell-based notebook UI on top of it using Jetpack Compose for the outer shell.

The result: a fully working, offline-capable data science notebook on Android — for free.

This is the feature that separates Codino from every other Python app on the Play Store. Most apps don't touch real libraries. I got them all for free through WebAssembly.

Website: pyodide.org

4. Google Gemini API — The Free AI Tutor

Every AI-powered learning app charges for the AI. Mimo charges. Sololearn charges. I didn't want to do that.

Google's Gemini API has a generous free tier — enough to give every Codino user real AI hints, full lesson explanations, and code understanding without paying anything.

How I use it inside Codino:

AI hint button inside each lesson → calls Gemini
AI explains quiz answers in markdown
AI explains code written in the IDE
Responses render as beautiful formatted markdown inside the app

The free tier limits are high enough that most users never hit them in a day of learning.

5. Groq — A Backup AI Provider That's Insanely Fast

Gemini is great, but having only one AI provider is risky. If it goes down or a user hits the daily limit, the AI feature breaks completely.

So I added Groq as a fallback.

Groq is a free AI inference API that runs open-source models (like LLaMA and Mixtral) at an almost unbelievable speed. It's the fastest AI API I've ever used.

My multi-provider strategy:

Try Gemini first (best quality, generous free tier)
Fall back to Groq if Gemini limit is hit (fast, free)
Optionally add OpenRouter for additional model variety

The user never sees any of this. They just get a response. The system handles it silently in the background.

This is how you build AI reliability for zero dollars. Don't depend on one provider.

6. Supabase — Free Backend and Auth

User accounts, streaks, leaderboard data, XP progress — all of that needs a backend.

Supabase is an open-source Firebase alternative with a very generous free tier:

500 MB database
Authentication built-in
Realtime subscriptions
REST and direct SDK support for Android

I used Supabase to store:

User profile and progress data
Streak history
Leaderboard scores
Daily AI quota tracking

It cost nothing.

7. Jetpack Compose — The UI That Looks Premium

The only way to make a free app feel premium is to make it look and animate beautifully.

Jetpack Compose is Google's modern Android UI toolkit. It's free, open-source, and very powerful for building smooth, animated UIs.

Everything you see in Codino — the dark UI, the smooth lesson transitions, the animated streak counter, the glowing leaderboard — was built purely with Compose and its animation APIs.

No paid UI libraries. No design assets I paid for.

8. Google Play Store — $25 One-Time Fee

This is the only money I spent.

The Google Play Store has a one-time developer registration fee of $25. After that, you can publish unlimited apps forever.

That $25 is the only real cost of building and shipping Codino.

The Honest Reality

Building with free tools is not the easy path. It comes with real challenges:

Pyodide is heavy. The first load inside WebView can be slow. You need to manage loading states carefully.
Free API tiers have limits. You have to build fallback logic, not just assume one provider works.
Sora Editor needs configuration. It's not a plug-and-play drop-in. You'll spend time tuning it.
Supabase free tier has row limits. You need to design your schema efficiently from day one.

But none of these problems cost money. They cost time. And time is the one resource a 19-year-old gap year developer has.

Final Thought

The biggest lie in software development is that you need money to build something real.

You don't.

You need Google, GitHub, patience, and a willingness to read documentation at 2am.

Codino is proof. A Python learning app with an offline IDE, AI tutor, Jupyter notebook, data science libraries, gamification, leaderboard, and free certificates — built by one person, from Bangladesh, with zero dollars.

If I can do it, so can you.

Codino is available on the Google Play Store. Search "Codino Learn Python" or click here.

Follow for more honest posts about building apps from scratch with no budget.

What If You Could Learn Python Entirely on Your Phone, Offline, for Free, and Get a Certificate at the End?

Simanta Das — Sat, 13 Jun 2026 10:56:56 +0000

Not hypothetically. Right now.

Most people who want to learn Python don't fail because they're not smart enough. They fail because good resources cost money, free ones are half-finished, and life doesn't always give you a quiet desk and stable internet.

No laptop. No Wi-Fi. No credit card. Just your phone and the time you already have sitting around.

Your commute is enough

Lessons are short and built to fit stolen moments — a bus ride, a lunch break, ten minutes before bed. The offline IDE keeps working even when the signal drops.

4.8 stars on the Play Store.

What's inside

Real offline IDE with autocompletion
AI Chat, AI Code Creation, in-lesson hints
Summary Tab to review without going backwards
Free certificate at the end — no paywall waiting for you

One thing worth knowing

There is no Pro version. No locked chapters. What you see is what you get.

Search Codino - Learn Python on the Google Play Store.

Codino — The Python Learning App That's 100% Free, Works Offline, and Actually Gives You a Certificate

Simanta Das — Sat, 13 Jun 2026 10:56:01 +0000

I got tired of apps that lock everything good behind a paywall. So I built one that doesn't.

Codino is a Python learning app for Android, rated 4.8 stars on the Play Store, and everything in it is completely free. No locked chapters. No subscription to claim your certificate. No fake IDE that stops working the moment you lose signal.

What's inside

Bite-sized lessons with the same horizontal scrolling style that makes learning feel easy
Real offline IDE with autocompletion and syntax highlighting — works in dead zones, on buses, anywhere
AI Chat for when you want to ask something freely without digging through lessons
AI Code Creation so you can see how things actually work in practice
Summary Tab to review everything you've covered without hunting backwards
Free Certificate when you finish — no conditions, no upgrade prompt, just yours

Why I built it

Every app I tried either paywalled the good stuff or gave me a fake sandbox that didn't behave like real Python.

I wanted something that treated learning seriously without treating learners like a revenue opportunity. Codino is the result of that frustration.

It's free right now because I believe access to learning shouldn't cost anything. That's not a temporary promotion — that's the whole point.

What people are saying

"4.8 stars on the Play Store" — and every review goes straight back into making it better.

Try it

Search Codino - Learn Python on the Google Play Store, or tap the link below.

If you try it, I genuinely want to know what you think. Drop a review or reach out directly — every piece of feedback shapes what gets built next.

Why I Stopped Using Mimo and Built My Own Python App

Simanta Das — Sat, 13 Jun 2026 10:29:22 +0000

I Was a Mimo User. A Loyal One, Actually.

I liked the clean UI, the bite-sized lessons, and the streak system. It made learning feel like a game, and for a while, that was enough. But then I hit a wall—not a knowledge wall, a paywall.

I wanted to access the advanced projects. Locked. The certificate at the end? Locked. Half the course I thought I was getting? Locked behind a subscription that costs more than my monthly phone bill.

I closed the app and just sat there a little annoyed.

The Thing No One Talks About With These Apps

I started looking at alternatives: Sololearn, Programiz, and a few others. They all had the same pattern: hook you with a free tier, make you feel progress, then ask for money right when things get interesting.

And the offline situation is genuinely bad across all of them. If I’m on a bus or in a dead zone, I’m basically stuck. Most apps simulate coding in a fake little sandbox that doesn’t even behave like real Python. You finish a lesson thinking you learned something, and then you open a real editor and have no idea what you’re doing.

I realized I wasn’t actually learning to code. I was learning to complete lessons.

So, I Decided to Build the Thing I Actually Wanted

I’m a developer. That’s not me being arrogant; that’s just the obvious next step when you’re frustrated enough. I started building Codino.

The first thing I knew for certain: It had to be completely free. No “free tier.” No locked chapters. No certificate behind a $15/month subscription. Free means free.
The second thing: A real IDE. Not a simulated one. An actual offline code editor with autocompletion and proper syntax highlighting—the kind that works in a dead zone on a moving bus. Because that’s when I actually have time to code.

What It Turned Into

Honestly, it grew beyond what I originally planned.

The lessons follow the same horizontal scrolling format that made Mimo enjoyable to use, but without stopping every few screens to ask for money. There’s an AI feature built into lessons that gives hints when you’re stuck, and the daily quota is generous—unlike apps that give you three AI hints and then say, “upgrade for more.”

I also added:

AI Chat: For when you want to just ask a question freely.
AI Code Creation: For when you want to see how something works in practice.
Summary Tab: So you can review what you’ve covered without digging back through lessons.
Free Certificate: Yes, the certificate is completely free.

Where It Is Now

Codino is new. I’m not going to pretend otherwise. The community is small, the download count is humble, and there’s plenty still to build.

But the core of it works:

The offline IDE works.
The AI features work.
The lessons work.
And it costs nothing.

I built it because I was tired of apps that treat learners like a revenue opportunity first and a student second. Whether that resonates with other people or not, I’m genuinely proud of what it is right now.

If you’re learning Python and you’re tired of hitting paywalls, give it a try. It’s on the Play Store, it’s called Codino, sitting at 4.8 stars, and it’s completely free. At least for now, I have no plans to change that.

If you’ve used Codino or have thoughts, drop them in the comments. I read everything.